Alloys at the Nanoscale; The Case of Nanoparticles

贵金属纳米颗粒在现代纳米技术中有着广泛的应用。事实上，文献中已经描述了从催化到医学、从光学到磁性的许多应用。然而，对它们的性质的理解还远远没有完全实现。例如，Au/Pd被发现是一种非常好的加氢催化剂，其活性远远高于这两种金属。此外，当金存在时，催化剂具有抗硫中毒的能力。然而，人们仍然缺乏对这些影响的清晰理解。该项目发起了一项了解双金属纳米颗粒结构和行为的两国努力。该项目由美国得克萨斯大学奥斯汀分校、新莱昂大学(UANL)、墨西哥波托西诺研究所(IPYCIT)和圣路易斯波托西大学(IFUASLP)共同开展，目的是利用分子动力学、先进的电子显微镜和受控合成技术，清楚地识别双金属颗粒优异性能的来源。金-钯、金-银、铂-金、铂-银、钯-银和钯-铂合金是特别有价值的。样品将在两个国家制备并交换以进行表征。分子动力学计算将在墨西哥实验室使用德克萨斯大学奥斯汀分校的超级计算机进行，电子显微镜和其他表征将在德克萨斯大学奥斯汀分校进行。该项目将为美国学生提供国际经验，他们将在墨西哥实验室度过一段时间。此外，访问德克萨斯大学奥斯汀分校的墨西哥学生将与美国少数族裔本科生联系在一起，并为这些学生提供榜样。预计这项工作的基础科学成果将有助于为氢燃料时代开发更好的催化剂。该奖项由美国国家科学基金会国际科学与工程办公室共同资助。

Nanoparticles of noble metals are widely used in modern nanotechnology. Indeed, many applications ranging from catalysis to medical, from optical to magnetic have been described in the literature. The understanding, however, of their properties is far from fully achieved. For instance, Au/Pd has being found to be an excellent hydrogenation catalyst with activity far superior to either metal. Also when gold is present the catalyst becomes resistant to sulfur poisoning. Yet, a clear understanding of these effects is still missing. This project launches a bi-national effort to understand the structure and behavior of bimetallic nanoparticles. The project is conducted by the University of Texas at Austin in the US, and the University of Nuevo Leon (UANL), the Instituto Potosino de Investigacion Cientifica (IPYCIT), and the Universidad Autonoma de San Luis Potosi (IFUASLP) in Mexico.The aim is to clearly identify, using molecular dynamics, advanced TEM and controlled synthesis, the origin of the outstanding properties of bimetallic particles. The alloys Au-Pd, Au-Ag, Pt-Au, Pt-Ag, Pd-Ag, and Pd-Pt are of special interest. Samples will be prepared in both countries and exchanged for characterization. The molecular dynamics calculations will be performed in the Mexican labs using the supercomputer at UT-Austin, electron microscopy and other characterization will be performed in UT-Austin. The project will provide international experiences to US students who will spend time in the Mexican laboratories. In addition, Mexican students visiting UT-Austin will be linked with US minority undergraduates and provide role models for those students. It is expected that fundamental science outcomes from this effort will assist the development of better catalysts for a hydrogen-fuel era.This award is co-funded by the NSF Office of International Science and Engineering.